1,1-Dichlorotetrafluoroethane (i.e., CF.sub.3 CCl.sub.2 F or CFC-114a) is of interest as an intermediate to 1,1,1,2-tetrafluoroethane (i.e., CF.sub.3 CH.sub.2 F or HFC-134a) which can be obtained via catalytic hydrogenolysis of its carbon-chlorine bonds using a supported metal hydrogenation catalyst (see e.g., C. Gervasutti et al., J. Fluorine Chem., 1981/82, 19, pgs. 1-20). HFC-134a is an environmentally acceptable potential replacement for chlorofluorocarbon (i.e., CFC) refrigerants, blowing agents, aerosol propellants and sterilants that are being viewed with concern in connection with the destruction of stratospheric ozone. It is highly desired that the 1,1-dichlorotetrafluoroethane employed in the hydrogenolysis route to HFC-134a has as low a content of 1,2-dichlorotetrafluoroethane (i.e., CF.sub.2 ClCF.sub.2 Cl or CFC-114) as practicable since the presence of CFC-114 during hydrogenolysis can lead to formation of 1,1,2,2-tetrafluoroethane (i.e., CHF.sub.2 CHF.sub.2 or HFC-134; see e.g., J. L. Bitner et al., U.S. Dep. Comm. Off. Tech. Serv. Rep. 136732, (1958), p. 25). HFC-134 mixed in HFC-134a may be objectionable for some applications depending on concentration and, since the two isomers boil only 7.degree. C. apart, separation of the isomers in high purity is difficult.
CF.sub.3 CCl.sub.2 F can be obtained by reacting CCl.sub.3 CF.sub.3 (i.e., 1,1,1-trichlorotrifluoroethane or CFC-113a) with HF using various catalysts. Normally, excess HF is used to achieve relatively favorable reactor rates. In vapor-phase processes, typical reactor products contain HCl, unreacted CF.sub.3 CCl.sub.3 and HF as well as CF.sub.3 CCl.sub.2 F. In liquid-phase processes the reactor products contain predominately HCl, CF.sub.3 CCl.sub.2 F and HF as well as traces of CF.sub.3 CCl.sub.3. HF may be removed from the halogenated hydrocarbon components of the product mixture using conventional aqueous solution scrubbing techniques. However, the production of substantial amounts of scrubbing discharge can create aqueous waste disposal concerns.
There remains a need for processes utilizing HF in such product mixtures as well as halogenated hydrocarbons therein such as CFC-113a and CFC-114a. Both CF.sub.3 CCl.sub.2 F and CCl.sub.3 CF.sub.3 (like their isomers) can be fluorinated by catalytic reaction with HF to form CF.sub.3 CF.sub.3 (i.e., perfluoroethane or PFC-116) a useful etchant compound (see e.g., PCT Patent Publication No. WO 93/17988).